PELHAM - William Martell estimates he's lost 60 percent of his business since the Quabbin Reservoir was closed to private recreational boats because of the threat of invasive zebra mussels.

Martell runs Gate 8 Boat and Bait Co., on Packardville Road, which leads right into Gate 8 at the Quabbin in Pelham.

He believes the decision to close the reservoir to private boaters - the majority of his business - was rushed.

"They didn't think about it. As far as I'm concerned it shouldn't have been made. I'm hoping (the ban) doesn't last 45 days," Martell said.

While he still gets some business from those visiting the Quabbin to shore fish or rent boats provided by the state, he said it's not like it usually is in July.

The decision to close the Quabbin, which provides drinking water to 2.5 million people, was announced on July 15 by the state Department of Conservation and Recreation and the Massachusetts Water Resources Authority.

Martell isn't the only business owner feeling the ban's effects.

Bait and sport shop owners and bait wholesalers throughout Western Massachusetts have noticed a slowdown, and they also have heard plenty of grumbling from fishermen whose favorite fishing spot has been taken away.

Though the ban is supposed to last 45 days, Conservation and Recreation Commissioner Richard K. Sullivan Jr. said he hopes it will end sooner.

Sullivan said officials realize this is the height of fishing season and that businesses, in addition to fishermen, are being affected.

Sullivan said there has been no sign of zebra mussels at Quabbin, and dive teams have been searching for them.

There is no known threat to the drinking water from zebra mussels, which are native to Russia. With acidic water and low calcium levels, the Quabbin is not considered a suitable environment for zebra mussels to grow their shells and survive.

The discovery of zebra mussels in Laurel Lake in the Berkshire County town of Lee prompted the decision to close Quabbin. These mussels hitchhike to water bodies by attaching themselves to boat hulls.

Officials acknowledged it is an act of "extreme caution" to ban private boats from the Quabbin.

Sullivan said they want to be careful because these mussels can choke off native vegetation, change the ecology of the environment and cluster in piping and other infrastructure.

So far, Laurel Lake is the only spot with the zebra mussels in Massachusetts, Sullivan said.

"It's a precautionary measure because of the drinking water supply," Sullivan said. "We are going to take this time to put in place protocols for invasive species."

Sullivan said it's possible that boats may be required to be cleaned before entering the Quabbin.

State Sen. Stephen M. Brewer, D-Barre, has written to state agencies and officials about his displeasure over the ban.

Brewer wants to get the recreational boats, which also includes canoes and kayaks in a limited area, back in the Quabbin as soon as possible.

"To deny access to the descendants of the towns of Dana, Enfield, Greenwich and Prescott is a great insult, especially in light of the sacrifices made by their forefathers for the people of eastern Massachusetts," Brewer wrote.

Those towns were flooded in the 1930s to create the reservoir.

Brewer called the restriction "an overreaction to a situation that is highly unlikely to occur in this body of water."

Richard M. Zolla, owner of Grizz Baits in Monson, a wholesale manufacturer, said he understands the concern about zebra mussels, but he cannot understand why the state would want to put businesses in financial peril when they would be at their busiest.

"It's bad enough now in this economy," Zolla said. "I don't think the MWRA, when it made this decision, really looked into everything."

Richard B. Hamilton, owner of Nick's Sport Shop in Palmer, said he won't feel it quite as much as bait shops, but said the closing will cut into sales.

Timothy L. Divoll, owner of Valley Sport in Easthampton, said he's also been affected. Divoll said fishermen will find somewhere else to fish, but noted that some, like himself, have boats specifically designed for use at Quabbin.

At R & R Sport Shop in Belchertown, owner Richard N. Kimball said last weekend was "extremely quiet" at his shop.

"There are so many regulars who go there on a daily basis. They buy bait. They buy lures. It's definitely affected our business. I'm not very happy about it, but I don't want to holler too loud," Kimball said.

"I'm concerned because whenever you lose anything, it's hard to get it back," Kimball said.